Bumpers perform as protectors of passengers and vehicles when collisions between vehicles or between vehicles and other things happen. Yet, the protective effects of bumpers are not satisfactory. It has been known that the presently used bumpers can be roughly classified into three categories, which are all-metal, rubber encapsulated, and rubber inlaid type. The all-metal type bumpers basically do not have buffering function and can not reduce any impact forces; the other two have some buffering function due to the encapsulated or inlaid rubber, but their buffering effects are not satisfactory.